Container handling frame

ABSTRACT

A frame for handling cargo containers is disclosed. A vertical member of the frame is mounted on the carriage of an industrial lift truck having an extensible mast. The housing at the upper end of the vertical member contains a pair of transversely extensible arms. Powered by a pair of hydraulic motors, these arms may be moved inwardly or outwardly along their longitudinal axis by the truck operator so as to position each arm to engage the upper corner fittings of a cargo container from one side. When thus positioned and engaged, the frame and truck may lift and move the cargo container.

United States Patent [191 Lynch et al.

[ 1 May 22, 1973 [54] CONTAINER HANDLING FRAME [75] Inventors: Peter D.Lynch, Portland, Oreg.; Dempsey R. Oldfield, Half Moon Bay, Calif.;Donald K. Zifka, Mill [21] Appl. No.: 61,284

3,166,207 1/1965 Quayle ..294/67 BB X 3,387,730 6/1968 Levitt ..214/6213,558,176 1/1971 Fathauer 294/81 SF X 3,182,837 5/1965 Farmer.... 294/67BB X 3,552,557 1/1971 Green ..214/620 3,514,146 5/1970 Zweifel et al.......294/81 SF X 3,387,729 6/1968 Hinden et a] ..214/621 PrimaryExaminer--Robert J. Spar Attorney-Francis Swanson [57] ABSTRACT A framefor handling cargo containers is disclosed. A vertical member of theframe is mounted on the carriage of an industrial lift truck having anextensible mast. The housing at the upper end of the vertical membercontains a pair of transversely extensible arms. Powered by a pair ofhydraulic motors, these arms may be moved inwardly or outwardly alongtheir longitudinal axis by the truck operator so as to position each armto engage the upper corner fittings of a cargo container from one side.When thus positioned and engaged, the frame and truck may lift and movethe cargo container.

1 Claim, 11 Drawing Figures Patented May 22, 1973 3 734 324 3Sheets-Sheet l :I fl ll INVENTORS PETER D. LYNCH DEMPSEY R. OLDFIELD ogw K. ZI FKA llfiome 7 Patented May 22, 1973 3,734,324

5 Sheets-Sheet 2 INVENTORS PETER D. LYNCH DEMPSEY R. OLDFIELD DONALD K.ZIFKA flfforney Patented May 22, 1973 3,734,324

5 Sheets-Sheet 3 PETER 0. LYNCH DEMPSEY R. OLDFIELD DONALD K. ZIFKA RmRu W l 8' INVENTORS CONTAINER HANDLING FRAME BACKGROUND OF THEINVENTION 1. Field of the Invention The present invention relates toframes for lifting and moving cargo containers and particularly toextensible container handling frames for use with an industrial truckhaving an upright and carriage.

2. Description of the Prior Art In recent years freight cargo containershave begun to play a significant role in the transportation industry.Such containers are uniform in size and shape and have a large capacity.They are constructed of a wide variety of materials and range in weight,when fully loaded, up to 75,000 lbs. I

These containers are usually 8 feet high, 8 feet wide, and commonly 20to 40 feet in length. The containers have standardized corner fittingswhich enable them to be moved by equipment commonly found at largerports, truck docks and rail terminals. These prior art devices includestraddle carriers, crane type machines, and industrial lift trucks withspecial front end attachments. The latter type of equipment is mostsimilar to the present invention. Such attachments usually consist of arigid horizontal rectangular frame attached to the forks of theindustrial truck. This rigid frame usually has a set of downwardlydepending latch mechanisms which engage the cargo container at the topof its four upper corner fittings. The container can then be picked upand moved. A limitation of such systems has been their inability tohandle more than one size container. A 20 foot container requires a 20foot handling frame; a 40 foot container, a 40 foot frame and so on.

A further limitation of such systems lies in their heavy weight whichrequires a larger capacity truck. Virtually all such systems have in thepast been top attaching.

SUMMARY OF THE INVENTION One requirement of all such industrialtruckcontainer handling attachment combinations is that they mustoperate from one side of the container. In accordance with the presentinvention an upright container frame handling attachment for use with anindustrial truck is provided. One object of the invention is to providea container handling frame that is adjustable to fit a wide range ofcontainer sizes.

A further object of the invention is to provide a container handlingframe that may satisfactorally pick up containers by attaching thefittings of one side only. A still further object of the invention is toprovide a container handling frame design wherein torque forces inducedin the extensible arms of the frame tend to cancel one another.

DESCRIPTION OF THE DRAWINGS The foregoing and other features, objectsand advantages of the present invention will be more apparent from thefollowing detailed description which proceeds with reference to theaccompanying drawings wherein:

FIG. 1 is a side view of an industrial truck showing the container framemounted on the carriage. A cargo container is shown in phantom.

FIG. 2 is an end view of the container handling frames housing, drivemechanism, and extensible arms, partially broken away to show interiordetails. The drawing also shows a break-away view of one containercorner fitting with a lifting hook from said extensible arm insertedwithin it.

FIG. 3 is a sectional view of the lifting hook taken along line 3-3 ofFIG. 2.

FIG. 4 is a sectional view of the drive mechanism taken along line 4-4of FIG. 2.

FIG. 5 is a perspective view of the container handling frame.

FIG. 6 is a perspective view of the bottom bumper.

FIG. 7 is a sectional view taken along line 7-7 in FIG. 5.

FIG. 8 is a perspective view of the lifting arm construction.

FIG. 9 is a diagram of forces at a lifting point on a container.

FIG. 10 is a diagram of hook forces in the general case.

FIG. 11 is a diagram of hook location for torque cancelling.

DETAILED DESCRIPTION Referring now to the drawings, the containerhandling frame has an upright member 10 mounted on the carriage 12 of anindustrial lift truck 14. The unit is shown engaging a cargo container16 in fittings 17. Member 10 has a housing 18 mounted at its upper end.The frame 10 also has a pair of diagonal bracing members ll connectingit to housing 18. The upright member 10 is also braced with a crossmember 13 and has a bumper plate 15 mounted at its lower end. Thehousing 18 contains a pair of extensible arms 20 and 22. Each extensiblearm has a rigid rectangular tube 24 mounted upon it. As viewed in FIG. 5the leftward extending arm 22 mounts a load lifting hook 26 at itsoutermost end. As viewed in FIG. 5 the rightward extending arm 20 mountsa loading hook 28 at its outermost end. The housing 18 has mounted onits upper side along its longitudinal axis, a pair of guide channels 30and brackets 31 which receive rigid rectangular tubes 24 from arms 20and 22. At the ends of each tube 24 is mounted a chain 32. Each chain 32is reeved under idler sprockets 34 mounted on housing 18. Each chain isfurther reeved over sprocket 36 which is mated to shaft 38 of hydraulicmotor 40 which is mounted on the housing 18 by means of brackets 42which also mount idlers 34.

From the hydraulic motors 40 supply lines 44 run to control valves 19.Oil from the conventional lift truck supply system is used to powermotors 40.

Thus far, this disclosure has been directed to the objects, advantages,and general characteristics of the invention. To completely understandthe nature of the invention it is necessary to turn to certainelementary theoretical considerations. The discussion following isoffered only in the qualitative sense and only for the purpose of moreclearly illustrating the invention. FIG. 9 shows an analysis of thehorizontal and vertical forces acting on a standard 8 by 8 containerwhen picked up from one side by that sides top fittings. The analysisassumes that load W of the container is horizontally centered. Thus theposition of the horizontal center of gravity (C6,) is four feet from oneedge of the container. Thus in an equilibrium condition the resultantforce in a vertical direction (R,,) will equal the weight of thecontainer load (W). Further, in an equilibrium condition the forceacting in a horizontal direction must equal zero. Thus from FIG. 9resultant forces at the upper edge (R,,) must equal the resultant forcesat the lower edge (R and R R Also, assuming equilibrium and picking thecontainer up at the corner pocket point P we have the sum of the momentsabout P EM, R (8 feet) W(4 feet) or R 12W. Substituting R for R and R,,for W, the expression reads R,, %R,, or R, 2R,,. From this it can beseen that the angle 0 of the resultant line of force acting throughpoint P is Tan 6 R /R 2. This is approximately equal to 6326 from thehorizontal, the tangent of this angle being 1.9998.

This relation holds true for any length container and for any verticalcenter of gravity as long as its cross section is square and it ishorizontally supported at its bottom edge by a bumper.

Now, if the container is to be picked up from one side, this relationassumes considerable importance in the placement of the loadliftinghooks on the transverse arms 20 and 22. Ideally the torque forcesinduced in beam 20 should be used to oppose and cancel the torque forcesinduced in beam 22. Using the relation previously derived from theresultant force in the container, it is now possible to determineprecisely where to place the load engaging hooks.

Refer now to FIG. 10. This shows the analysis of the general case forplacing the hooks. B is a cross-section of a beam B with a hook H on it.S is the shear center of the beam B. The shear center of a beam. isdefined and described in detail at pages 97 to l 1 1 of the bookAdvanced Mechanics of Materials, second edition 1952, written by Fred B.Seely and James O. Smith, and published by John Wiley & Sons, New York.

Consider now a force directed along the line of action R at the point Pon the hook H. This force can be resolved into its horizontal componentR and its vertical component R,,. The value of R, is R cos 0 and thevalue of R, is R sin 0. D is the perpendicular distance from shearcenter S to P in the horizontal plane. D is the perpendicular distancefrom S to P in the vertical plane. Thus the product of R, and D willproduce a clockwise torque of T about shear center S Likewise theproduct of R and D will produce a counterclockwise torque T about shearcenter S The hook can be placed so that the line of action passingthrough P will satisfy the following relation: R, X D R,, X 0,. Underthis condition the sum of the torque forces induced in the beam is zero.This means that the line, of action R also passes through the shearcenter S, as well as P.

It is easily seen that where point P is placed so that the line ofaction R, when directed downward and to the right as in FIG. 10, lies atthe left of the shear center 8,, a counterclockwise torque will result.Likewise, placement of the point P so that the line of action R, whendirected downward and to the right as in FIG. 10, lies to the right ofthe shear center 8,, a clockwise torque will result. This relationshipis true for any shape of beam and downward orientation of the line ofaction relative to the shear center and may be used to determine theplacement of hooks in all cases. From this analysis it is seen that byadjusting either D or D, or both in combination it is possible to applya clockwise or counterclockwise torque of known value to the beam B.

FIG. 1B represents the analysis of hook 26 and hook 6 28 of theinvention and is a specific case covered by the general case shown inFIG. 10. From the analysis of FIG. 9 the line of action on a containerbeing picked up is approximately 6326 to the horizontal and forcecomponent R, 2R,,. When hooks as in FIG. 11 pick up the container, theline of action R is the same as R in FIG. 9 and R, and R, in FIGS. 9 andII have the same values. In a design employing side-by-side arms as inthis invention, the shear centers of the respective beams are placed sothat the dimension D of FIG. 11 is constant for both hooks. This isreadily seen from FIG. 2. Therefore the balancing of torque forces isdependent on the relation between the constant D and the dimensions D,and L, which must necessarily be different in each arm and hook as inFIG. 2.

In FIG. 1 1 it is seen that for the torque forces to cancel thefollowing relation must be satisfied:

Substituting 2R for R, in the above and solving, we have:

This relationship defines the placement of the hooks to achieve torquecancelling.

OPERATION To illustrate the operation of the container handling frameassume that the operator of truck 14 wishes to pick up a 40 footcontainer and the extensible arms 20 and 22 of the container handlingframe are positioned to pick up only a 20 foot container. As in FIG. 1,the operator approaches container 16 from one side. He elevates carriage12 until it is approximately level with the top container 16. Using thecontrols 19 on the truck 14 the operator extends arms 20 and 22independently until each is properly aligned with its respective topfitting 17. When the controls 19 are actuated to move either one of theextensible arms, the hydraulic motor 40 for the appropriate arm, whichis mounted on housing 18, begins. to turn. Sprocket 36 of motor 40 isengaged with chain 32 which is fastened at both ends to tube 24 aspreviously stated. The turning of sprocket 36 causes movement of chain32 which in turn moves the arm in the direction desired. After movingload hooks 26 and 28 into positions opposite fitting 17, the operatortilts the carriage l2 forward slightly and drives the truck slowlyforward until said hooks are inserted into said pockets. The operatorthen raises the carriage l2 and brings the container 16 to bear againstbumper 15. The container may now be elevated and moved by the truck toany desired location. To deposit the container 16 and disengage thecontainer handling frame, the above sequence of steps is merelyreversed.

Having illustrated and described the preferred embodiment of ourinvention, other modifications in arrangement and detail will occur tothose skilled in the art. We claim as our invention all such inventionsas come within the true spirit and scope of the following claims:

We claim:

1. A cargo container handling frame including an upright member;

means for mounting said frame on a lift truck carriage;

unitary housing means mounted horizontally on said upright member;

bumper means mounted at the lower end of said upright member;

front and rear load lifting arms reciprocally mounted in a horizontalplane in side by side relation at least partially within said housing;

a first hook mounted on said rear arm, the load engaging portion of saidhook positioned below and 5 protruding substantially outward from thefront side of said arm so as to apply torque about the longitudinal axisof said arm when lifting a load;

a second hook mounted on said front arm, the load engaging portion ofsaid hook positioned below within said housing when said arms lift aload.

1. A cargo container handling frame including an upright member; means for mounting said frame on a lift truck carriage; unitary housing means mounted horizontally on said upright member; bumper means mounted at the lower end of said upright member; front and rear load lifting arms reciprocally mounted in a horizontal plane in side by side relation at least partially within said housing; a first hook mounted on said rear arm, the load engaging portion of said hook positioned below and protruding substantially outward from the front side of said arm so as to apply torque about the longitudinal axis of said arm when lifting a load; a second hook mounted on said front arm, the load engaging portion of Said hook positioned below and to the forward side of the longitudinal axis of said arm so as to apply a torque about said longitudinal axis substantially equal to and opposite that applied to said rear arm when lifting a load; whereby torque forces applied to said rear arm acting within said housing oppose and substantially cancel torque forces applied to said front arm acting within said housing when said arms lift a load. 